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目的建立毛细管区带电泳间接紫外测定食品中木糖醇的新方法。方法样品用超纯水提取后离心,过0.45μm膜后上机进样。以未涂敷熔融石英毛细管(50μm×60.2 cm)为毛细管分离柱,以8 mmol/L 3,5-二硝基苯甲酸、10 mmol/L硼砂和0.5 mmol/L十六烷基三甲基溴化铵为分离缓冲溶液。分离电压为-20 k V,检测波长为200 nm,用外标法定量。结果方法检出限为3.00 mg/L(S/N=3),定量限为10.00 mg/L(S/N=9),线性范围为10.00~300.0 mg/L,线性相关系数r为0.9994。在20.00、40.00、80.00 mg/L添加水平下,平均回收率分别为103.2%、103.3%及104.8%,相对标准偏差分别为0.5%、1.2%及0.7%(n=3)。结论该方法简单快速,11 min内即可完成一次样品分析(清洗6 min、分离5 min),试剂及样品消耗量少,适用于食品中木糖醇的检测。
Objective To establish a new method for determination of xylitol in food by capillary zone electrophoresis with indirect ultraviolet. Methods The samples were extracted with ultrapure water and centrifuged. Uncoated fused silica capillaries (50 μm × 60.2 cm) were used as the capillary separation column, and 8 mmol / L 3,5-dinitrobenzoic acid, 10 mmol / L borax and 0.5 mmol / L cetyltrimethyl Ammonium bromide is an isolated buffer solution. The separation voltage was -20 kV and the detection wavelength was 200 nm, quantified by external standard method. Results The limit of detection (LOD) was 3.00 mg / L (S / N = 3). The limit of quantification was 10.00 mg / L (S / N = 9). The linear range was 10.00-300.0 mg / L and the linear correlation coefficient was 0.9994. The average recoveries were 103.2%, 103.3% and 104.8% at 20.00, 40.00 and 80.00 mg / L, respectively. The relative standard deviations were 0.5%, 1.2% and 0.7%, respectively. Conclusion The method is simple and rapid, and can complete a sample analysis within 11 min (6 min of washing, 5 min of separation). The reagent and sample consume less, which is suitable for the detection of xylitol in food.